Gaseous surge protector



April 14, 19 59 J. E; JENNINGS 2,882,433

' GASEOUS SURGE PROTECTOR Filed Sept. 16. 1957 v l v l I 5 I 1 I I I 4 /2 4a INVENTOR. L/O EMMET'T JENNINGS his ATTORNEY United States Patent GASEOUS SURGE PROTECTOR Application September 16, 1957, Serial No. 684,292

'5 Claims. (Cl. 313-185) My invention relates to a gaseous surge protector or voltage regulator; and a principal object of the invention is the provision of a low cost implement without sacrifice of efliciency or durability.

Another object of the invention is the provision of a surge protector or voltage regulator operative over a relatively wide range of current and voltage without further adjustment after assembly,

Another object is the provision of a surge protector which will operate in an oscillating circuit.

Still another object of my invention is the provision of a surge protector or voltage regulator characterized by an almost instantaneous beginning of its operation, and an efliciently complete dissipation of generated heat.

Another object is the provision of a surge protector for direct current circuits so constructed that the negative terminal which develops heat during operation, presents an extensive radiating surface so that the temperature of the unit as a whole remains within a permissive range.

Still another object of my invention is the provision of a surge protector which can be used to clip high voltage pulses.

The invention possesses other objects some of which with the foregoing will be brought out in the following description of the invention. I do not limit myself to the showing made by the said description and the drawings, since I may adopt variant forms of the invention within the scope of the appended claims.

The figure of the drawing is a full scale elevation of my surge protector shown partly in half section.

My surge protector comprises a gas filled envelope, partly of glass and partly of copper, a relatively large area of copper hermetically closing one side of a glass bowl or shell. Essentially the copper closure comprises the negative terminal of the device, for the most efiicient operation.

The positive terminal is a large metal plate inside the envelope and spaced a short distance from the inside surface of the closure. It is supported on a long and slender conductive stem traversing the envelope and fixed in and passing through its dielectric wall in which it is hermetically sealed.

Externally the stem provides a connecting lead. Inside the envelope the stem ends in a sharp point extending from the face of the positive terminal plate nearest the negative terminal to a calculated distance therefrom. In use, the discharge begins from this point and immediately spreads to the larger flat surface of the metal plate and negative terminal.

The envelope is filled with one of the inert gases such as argon or nitrogen at a pressure usually between 27" and 29" of mercury. Spacing between positive and negative terminals, and gas pressure are near-critical values with relation to voltage and current; and are closely controlled during manufacture of the surge protector, first values being set by test with voltage in the rated range.

For example, assuming use with direct current of Patented Apr. 14, 1959 amperes at 250-300 volts, the point on the positive terminal plate may extend .125" beyond its surface, and the point lie .025 from the negative terminal.

The envelope first cleaned and vacuumized to a high degree may then be filled with argon at a pressure of about 27 /2 of mercury. For a range of 400 to 500 volts the gas pressure would be raised to 28 /2" or 29". If the expected or rated voltage was to be in the 5000 range, preferably nitrogen at atmospheric pressure would be substituted for the argon, and the spacing between the point and negative terminal would be increased to .125". in the 50,000 volt range. Selection of the inert gas has relation to its availability and cost, as well as to its physical qualities.

In detail, my surge protector or voltage regulator comprises a dielectric bowl or shell 2, conveniently of glass, to the rim bead 3 of which a metal closure conveniently of copper is hermetically united. The closure comprises a centrally located heavy circular base plate 4, having the compound rim flange 6. From the outer edge of the compound flange extends the slightly conical sealing flange 7, the feathered edge of which is embedded in the glass rim head 3 in a conventional hermetically tight union.

The closure is usually formed from a single copper sheet but when additional rigidity is required in the back plate portion, a copper reinforcing disk 4a may be brazed on the inside face of the back plate as shown.

While exact shape or conformation of my protector is not important per se, the globular bowl and circular pattern about a central axis lend themselves fully to the rapid and economical manufacture of a precision implement.

Fixed in the glass head 8, later coalesced with the wall of the glass bowl at about its center is a long slender tungsten conductor stem 9. 0n the outside of the shell the stem provides a lead 10 for connection to positive potential. On the inside of the shell, the stem terminates in a trigger or igniter point 12, spaced a minimum of about .025" from the inner face of the base plate.

Integrally united with the stem about .125 from its extreme point is a thin metal plate or disk 13 preferably of nickel and about .020" thick. The disk which constitutes the positive terminal is parallel to the base plate which constitutes the negative terminal, and is separated from it by a distance varying from .025 to .060" according to voltage to be discharged and dictated by the proposed use of the implement, as previously explained.

My surge protector will operate without a point, but a higher voltage is required to start the discharge. Because most applications require a very close voltage control, the point 12 is of first importance since it triggers or ignites the discharge which then spreads over the flat surface of the disk 13.

In operation, the negative terminal 4 develops heat while the positive terminal 13 remains cool. Owing to the large surface area of the copper closure structure 467 which includes the negative terminal, the heat generated by the discharge of over-voltage is dissipated by radiation into the surrounding atmosphere, and in some small part by conduction into and radiation from the metallic bracket in which the unit is customarily mounted.

If high currents are appearing at irregular intervals and of short duration, they can be considered as pulses; and my regulator can be used for clipping high or low voltage pulses when included in a suitably related circuit.

1 claim:

1. A surge protector comprising an hermetically tight envelope having a dielectric bowl closed by a metallic closure hermetically united with the bowl rim and in- This might be increased to .625" for a rating a cluding a base plate constituting the negative terminal of the implement, a conductive stem fixed in the wall of the bowl to provide a lead on the outside thereof and extending within the envelope into a predetermined spacing from the base plate, and a plate constituting the positive terminal of the implement mounted on the stem within the envelope and selectively spaced from the base plate.

2. A surge protector in accordance with claim 1 in which the envelope is filled to a pressure between 27 and 29 inches of mercury, with an inert gas selected from the group which consists of nitrogen and argon.

3. 'A surge protector in accordance with claim 1 in which the envelope is filled to a pressure approaching atmospheric with an inert gas. I

References Cited in the file of this patent UNITED STATES PATENTS 2,046,233 Audain June 30, 1936 2,201,003 Berkey May 14, 1940 2,242,042 Paetow May 13; 1941 2,661,439 Stoelting V... Dec. 1, 1953 

